Spring Wildlife Update
April has been active at WWT Arundel and the air is full of birdsong.
Warblers and sand martins returned, and a pair of marsh harriers are nesting in the reedbed again this year! Mallard ducklings, greylag and Canada goslings are waddling about with coot and moorhen chicks chase parents, screeching for morsels. The buzz of solitary and bumblebees drifts across the breeze, while your eyes enjoy the beauty of butterflies and damselflies on sunnier days!
Sand martins return
Spring has seen a strong and encouraging return of sand martins to WWT Arundel, with a handful of birds first appearing in late March. Those arriving in early April quickly got down to nest building.
We watched sand martins collecting plant material from nearby islands and carrying it into nest holes in the banks of the Sand Martin Hide. Several of these holes have been used successfully every year since 2020, and last season 150 of the 299 available nest holes were occupied. This highlights the long‑term importance of the site for this migratory species. As April progressed, numbers steadily increased, with nest‑building activity expanding into the wings of the Sand Martin Hide.
By mid to late April, sand martins had become one of the standout features of the reserve. Their fast, acrobatic flight delights visitors, with flocks sometimes numbering over 100 birds swirling low over the water around the Sand Martin Hide and the Scrape. Feeding busily and popping in and out of nesting banks, their constant movement and calls bring real energy to the wetlands and signal that spring migration — and the breeding season — is well underway.
Oystercatchers arrive early
A pair of oystercatchers returned to the wetlands in mid‑February. We usually welcome two nesting pairs each spring, and both appear to be onsite in April, although they have not yet settled on nesting spots. Their bold black‑and‑white plumage and bright orange‑red bills make them easy to spot.
One pair often chooses the roof of the Sand Martin Hide or nearby islands among the black‑headed gull colony to nest. Last year, a pair attempted to nest in Pelican Cove, but the attempt was not successful.
Oystercatchers create simple scrape nests on flat, open ground where they have clear views in all directions. They sometimes choose busy or ‘active’ areas as a way of reducing the risk from predators. In previous years, oystercatchers have nested among black‑headed gulls, which provide an extra layer of protection by raising the alarm when predators approach.
Look out for lapwing
Two pairs of lapwings remained at WWT Arundel after the winter flocks dispersed. One female appears to be sitting on a nest on the wet grassland, while the other pair have been seen mating and displaying.
Nest scraping is part of their display ‘dance’. Females lay four to five stone‑coloured eggs in these shallow scrape nests. Lapwings prefer areas of short vegetation, allowing them to spot predators early.
Marsh harriers in the reedbed
One or both birds from a marsh harrier pair have been showing well over the reedbeds on most mornings this spring. We have seen them carrying nesting material, suggesting the pair may breed onsite again.
2025 was the first confirmed year that marsh harriers bred at WWT Arundel. From July, we were able to watch the pair raising three youngsters, with noisy practice flights over the reedbeds — the first time juvenile marsh harriers had been recorded onsite.
Warblers and more
With spring in full swing, the reserve is alive with birdsong. Sedge and reed warblers have returned to breed, joining other warblers that have been singing for weeks, including blackcap, Cetti’s warbler and chiffchaff, with the occasional whitethroat now also heard.
A nightingale was seen and heard for a few days at the back of the Lost Reedbed. Tits and finches of various species are also busy singing and nest building — a wonderful sign that the breeding season is fully underway.
Buzzing about
Butterflies including peacock, comma, red admiral, brimstone, common blue and orange tip, have been appearing on sunnier days and in the past week or so we have seen the emergence of large red damselflies. A few hairy dragonflies have been spotted as well. Don't miss our May Moth Morning on May 13 to help the team ID the moths or just get some amazing close-ups with your camera.
